During the weekend, I was not able to use my new NetBSD system as I was back home using my Ubuntu desktop. Now that I returned back to the town where I study economics and business administration, I am right now reinstalling the system.
Actually there was nothing really wrong in the way I had originally installed the NetBSD. I just made the mistake of trying to use the wonderful packages system that installs all the packages by compiling them from the sources. Unfortunately, the packages collection takes a huge amount of my limited disk space.
Furthermore, it takes hours to compile anything at all with this machine. So it seems that I have to use binary packages of the applications in the future. If you intend to use NetBSD on anything built during the last couple of years, you will most probably be quite happy to use the source-based packages. See the pkgsrc guide for extensive documentation of the system!
The unix way of doing the cleanup of the system would probably have been to rm some directories by hand and tweaking some configuration files. As I have nothing special installed on the system - it was just configured to be a basic but usable command line system - I figured a reinstall would be easier and faster than reading some more of the great NetBSD documentation just to make sure I have removed everything unnecessary.
Now I have again a clean system, with just a root and one ordinary user created. I'm back in the beginning - and slowly learning to use the vim.